S-Nitrosothiols (RSNOs) are a unique class of molecules that only recently have begun to be investigated in detail after their discovery in vivo. RSNOs can release NO, and now appear as important players in the posttranslational modification and regulation of proteins. The chemistry and biology of RSNOs is not well understood, and mechanisms for their formation and decomposition remain unclear. The pore forming protein ?-hemolysin (?-HL) will be used as a nanoreactor to explore the chemistry of RSNOs at the single molecule using single channel recordings. A better understanding of the chemistry of RSNOs will not only shed light on possible biologically relevant reactions, but also assist in the design and identification of novel and effective RSNOs for therapeutic uses. The specific aims include the construction of an ?-HL pore that responds to RSNOs, followed by investigation into reactions involving RSNOs at the single molecule level, and subsequent characterization and identification of novel RSNO leads of therapeutic value. The expected outcomes include a better understanding of the mechanism for formation and decomposition of RSNOs, as well as the acquisition of kinetic and thermodynamic data of RSNO chemistry at the single molecule level.